Conversion of hydrocarbon oils



1 K. SWARTWOOD 2,059,290 Y I CONVERSION OF HYDROCARBON OILS v OriginalFiled Dot. 2e, 1953 FRACTIONATOR CONDENSER FURNACE TOPPING ANDFRACTIONATING VAPOR IZ INC AND TING FURNACE 2o FURNACE RECEIVERhydrocarbon oils of Patented Nov. 3, 1936 PATEN T F F11 CE 2,059,290CONVERSION OF HYDROCARBON OILS Kenneth Swartwood, Chicago, 111.,Universal Oil Products Company,

assignor to Chicago, 111.,

a corporation of Delaware Application October 26, 1933, Serial No.695,268

enewed 7 Claims.

This invention relates to and apparatus for an improved process thefractional distillation of relatively wide boiling range, such as crudepetroleum, accompanied by pyrolytic conversion of all but the desirablelow-boiling fractions of the charging stock and further conversion ofthe insufficiently converted intermediate products of the process toproduce high yields of desirable low-boiling distillate, such as motorfuel of high antiknock value, and good quality fuel oil residue.

One specific embodiment of the present invention comprises subjectinghydrocarbon oil, such as crude petroleum, to fractional distillation,recovering its desirable low-boiling fractions, subjecting itsintermediate fractions to conversion temperature at superatmosphericpressure in a heating coil, introducing the resulting products into areduced pressure vaporizing chamber, subjecting bottoms from the toppingoperation to conversion temperature at superatmospheric pressure in aseparate heating coil, subjecting the resulting products to vaporizationand fractionation, subjecting fractionated vapors of the desiredendboiling point to condensation and collecting the resulting products,returning low-boiling components of the reflux condensate produced bysaid fractionation to the first mentioned heating coil for furtherconversion, supplying bottoms from said fractionation'and vaporizingstage to said reduced pressure vaporizing chamber, subjecting vaporousproducts from the vaporizing chamber to fractionation, subjectingfractionated vapors of the desired end-boiling point to condensation andcollecting the resulting products, subjecting reflux condensateresulting from the'last vmentioned fractionating stage to conversiontemperature at superatmospheric pressure in another separate heatingcoil and, if desired, a communicating reaction chamber and introducingthe resulting vaporous and liquid conversion products into said reducedpressure vaporizing chamber.

One of the features of the invention is the provision for subjecting thebottoms from the topping operation (high-boiling fractions of thecharging stock) to a mild cracking or viscosity breaking operation in asingle pass through a heating coil and subjecting the resulting residualconversion products to further vaporization for 'the production of goodquality fuel oil.

Another advantageous feature of the invention resides in the provisionfor subjecting intermediate fractions of the charging stock, resultingfrom the topping operation, to conversion, to-

March 18, 1935 gether with corresponding intermediate fractionsresulting from the relatively mild oncethrough conversion of thehigh-boiling fractions of the charging stock, to conversion underindependently controlled conditions in a single pass through a separateheating coil.

Another feature of the invention provides for cooling the hot conversionproducts from the heating coil to which the intermediate fractions ofthe charging stock .and intermediate con- 10 version products from thefirst or relatively mild cracking stage of the process are supplied to atemperature at whichtheir excessive conversion is prevented, bycommingling therewith highboiling conversion products resulting from thefirst cracking stage of the process whereby to heat the lattersufficiently to effect their mild continued conversion and substantialfurther vaporization.

The accompanying diagrammatic drawing illustrates one specific form ofapparatus in which the process may be practiced.

, Referring in detail to the drawing, raw oil charging stock for theprocess, preferably comprising an oil of relatively wide boiling range,such as crude petroleum, for example, is heated to a temperaturesuflicient to effect its substantial vaporization by a well known means,not illustrated in the drawing, and is supplied in heated state throughline i and valve 2 to topping and fractionating column 3, wherein it maybe separated into low-boiling, high-boiling and intermediate fractions.

Any desired low-boiling fractions of the charging stock, comprising, forexample, gasoline or light gasoline fractions of satisfactory antiknockvalue, may be withdrawn from the upper portion of column 3 through line4 and valve 5 to condenser 6, wherein they are subjected to condensationand cooling. The resulting distillate and gas passes through line 1 andvalve '8 to collection and separation in receiver 9. Uncondensable gasmay be released from the receiver through line iii and valve ll.Distillate may be withdrawn from this zone through line l2 and valve I3to storage or to any desired further treatment. If desired, a regulatedportion of the distillate collected in receiver 9 may be recirculated bywell known means, not shown in the drawing, to the upper portion ofcolumn 3 to and fractionation of the vapors in this zone and to maintainthe desired vapor outlet temperature from the column, thus regulatingthe end-boiling point of the overhead distillate prodnot.

antiknock value boiling fractions toms, light gas oil and t from anysuitable inter Intermediate fractions of the charging stock, comprising,for example, any gasoline or highand valve (5 to pump l8 by means ofwhich this material is supplied through line I! and valve H! toconversion in heating coil l9.

discharged through line 2! and valve 22 into vaporizing chamber 23.Prefeably the stream of tially reduced pressure relative to thatemployed including its components boillng above the range densable gasmay be released from the receiver through line 40 and valve 4|.Distillate may be withdrawn from receiver 39 through line 42 anddensate, comprising, for example, any motor fuel or high-boiling motorfuel fractions of inferior as well as, when desi pressure distillatebothe like, are withdrawn mediate point or points ple, through line 44and in vaporizing cha mingled oils from ously described.

2| are supplied as previulting distillate a and valve 63 cooling. Theres through line 62 separation in receiver 64. may be releas and valve68.

nd gas passes to collection and Uncondensable gas ver 64 through linemay be withdrawn ed from recei regulating the enddistillate product fComponents of t to fractionator 58,

rom this zone.

which is withdraw fractionator ower portion of the and valve "I0 to hereflux condenthrough line 72 and wherein it is subjected 75 through line69 Pump "H supplies t fractionator 58 valve 13 to heating coil M,

. let from the. heating coil to ,fractions of the charging sure,measured. at this point in the system,

i and ber 19 through line they pass through line 80 and line 2| intovaporu topping. and fractionating equipment.

ably. a conversion to further conversion,preferably-at superatrnosphericpressure, by means of heat supplied from a furnace -15 of anysuit-ableform. -Thehot conversion products are dischargedfrom heating-coil 74through line 16 andmay pass,-al1 or'inpart, either through line "l1 andvalve -l'Binto reaction chamber 19 or through line 80, valve at and linei2l directto vaporizing chamber 23.

Reaction chamber '19, when utilized, is preferably operated at' asuperatmospheric pressure, -which maybe substantially equalized withthat maintainedat the outlet from heating coil 14 or may be somewhatreduced. Although not illustrated, chamber 19 is also preferably wellinsulated to prevent the excessive loss of heat from this zone. byradiation so that conversion of the products supplied thereto fromheating coil 14,

more particularly their vaporous components, may continue in thereaction chamber In the casehere illustrated, both vaporous and liqnid.conversion products are'withdrawn'in commingled state fromthelowerportion of cham- 82 and valve 83, from which izing chamber 23,.togetherwith the commingled products from heating coil l9 and from the lowerportion of column 33.

Any desired pressure'ranging'from' substantially atmospheric orsubatmospheric to a superatmospheric pressure of 200 pounds, or more,

I per square inch, may be employed for the frac- .erably within therangeof 300 to 1000 pounds,

- or, thereabouts, per square inch, although, when ,.desired, lowerpressures i to 950 F.,.orthereabouts,

down to substantially atmospheric may be employed in this zone. Aconversion temperature within the range .of 800 is preferably employedat the outlet from the heating coil to which highboiling fractions ofthe charging stock are supplied and preferably a superatmosphericpressure of from 100 to 500 pounds, or thereabouts, per square inch,.isemployed at this point in the systemand may be either substantiallyequalized or reduced in the succeeding vaporizing and fracv tionatingcolumn. The heating coil of the last conversion stage of the process, towhich only reflux condensate from the. same stage is returned forfurther conversion, may utilize an outfor example, of from 850 to 950F., or thereabouts, preferably with .asuperatmospherio pressure,measured at the outlet; from the heating coil, of the orderof 100 to500, pounds, or more, per square inch.

. As already mentioned, substantially .the same or somewhat reducedsuperatmospheric pressure may be utilized in the succeeding reactionchamber, when such a zone is employed, and a substantially reducedpressure ranging, for example, from 100 pounds, or thereabouts, persquare inch .to substantially atmospheric is preferred in the vaporizingchamber. Substantially equalized or somewhat reduced pressures, relativeto that employed in the vaporizing chamber,..may be utilized in thesucceeding fractionating, condensing and collecting portions of thesystem.

of the last mentioned cracking stage.

mediate fractions from this stage of the process, boiling betweenapproximately 350 to 550 F. are returned to the heating coil of thefirst square inch. Vapors from the vaporizing As a specific-example ofone 'of the many possible operations of the process of the presentinvention as it may be practiced in an apparatus such as illustrated andabove described: :the charging stock is anOklahoma crude of about it 50A. P.'- I. gravity, containing about 50 percent of material boiling upto 400 but of poor anti-knock value,-and the charging stock is subjectedto fractional distillationwhereby about 2'7 percent of light gasolinefractionslilO having an end-boiling point of about 250 F. and of goodantikno'ck value are recovered. Intermediate fractions of the chargingstock, boiling between aproximately 250 and 550 F. and comprising about43 percent of the crude, are subjected to a conversion temperature ofapproximately 980 F. at a superatmospheric pressure of (about 800 poundsper square inch. The remainder of the charging stock, comprising itshigh-boiling fractions, are separately subjected to a conversiontemperature of about 920 F. at a superatmospheric pressure of about 300pounds per square inch. A motor fuel of about 350 F. end-boiling pointand of good antiknock value is recovered as the light distillateproduct-'= Intermentioned cracking stage; for further conversio togetherwith said intermediate fractions of the charging stock. The higherboilingconversion products from the last mentioned cracking stage arecommingled with the highly heated prod: note from the heating coil ofthe'first cracking stage and the commingled oils are introduced into avaporizing chamber operated at-a superatmospheric pressure of about-75pounds per chamber are subjected to fractionation whereby 211 motor fuelof about 400 F. end-boiling point and of good antiknock value isrecovered as the overheaddistillate product and reflux condensate fromthe fractionator is subjected to further conversion ata temperature ofabout 950 F. and a superatmospheric pressure ofapproximately 400 poundsper square inch and the resulting vaporous andliquid conversion productsare introduced into" the vaporizing chamber.

-An operation such as above described may yieldyper barrel of chargingstock, about "70 percent of -motor fuel having an antiknock valueequivalent to an octane number of approximately '72 and about '20percent of good quality fuel oil residue, the remaining 10 percent, orthere-" abouts, being chargeable, principally, to uncondensable gas andloss.

I claim asmy invention:

1. In a process for the conversion of hydrocarbon oils wherein raw oilcharging stock for the process is subjected to fractional distillationto separate it into desirable low-boiling components, which arecondensed, intermediate components .and high-boiling components, theintermediate components subjected to pyrolytic-' conversion at elevatedtemperature and super- .atmospheric pressure, the high-boilingcomponents subjected to pyrolytic conversion under relatively lesssevere conditions of elevated temperature and superatmospheric pressureand the products resulting from said pyrolytic conversion of thehigh-boiling components subjected to vaporization and fractionationwhereby they are separated into desirable low-boiling products, whichare condensed, insuiiiciently converted'in-" jecting a hydrocarbondistillate to cracking conditions of temperature and pressure in aheating coil and subsequently discharging the same into a reducedpressure vaporizing chamber, simultaneously subjecting a topped crudeoil in a second heating coil to a relatively mild cracking treatment ofa viscosity reducing character and subjecting the resultant products tovaporization and fractionation independently of the heated products fromthe first-named coil, supplying bottoms and reflux condensate from thisvaporization and fractionation stage to said chamber and first-namedcoil respectively, separating vapors from unvaporized oil in saidchamber and withdrawing the unvaporized oil from the process,fractionating the vapors to condense heavier fractions thereof andsubjecting resultant reflux condensate to independently controlledcracking conditions of temperature and pressure in a third heating coilmaintained at higher temperature than said second coil, introducingconversion products of the last named reflux condensate into saidchamber, and finally condensing the fractionated vapors.

6. A conversion process which comprises subjecting a straight runhydrocarbon distillate to cracking conditions of temperature andpressure in a heating coil and subsequently discharging the same into areduced pressure vaporizing chamber, simultaneously subjecting a toppedcrude oil in a second heating coil to a relatively mild crackingtreatment of a viscosity reducing character and subjecting the resultantproducts tovaporization and fractionation independently of the heatedproducts from the first-named coil, passing bottoms from thisvaporization and fractionation stage to said chamber, supplying refluxcondensate from said stage to the firstnamed coil for cracking treatmenttherein together with said straight run distillate, separating vaporsfrom unvapo-rized oil in said chamber and withdrawing the unvaporizedoil from the process, fractionating the vapors to condense heavierfractions thereof and subjecting resultant reflux condensate toindependently controlled cracking conditions of temperature and pressurein a third heating coil, introducing conversion products of thelast-named reflux condensate into said chamber, and finally condensingthe fractionated vapors.

'7. The process as defined in claim 6 further characterized in that saidstraight run distillate contains hydrocarbons boiling within thegasoline range and is subjected in the first-named coil to highercracking temperature than the lastnamed reflux condensate in the thirdcoil.

KENNETH SWARTWOOD.

